We think about them every day - calories!
But have you ever stopped to think what a calorie is as a unit of measure?
Well, lets find out once and for all.
Firstly, it's important to remember a calorie isn't a tangible thing you'd find in food
or drink - like protein or carbs for example.
It's a metric unit we often use for measuring the energy value of food and drink, or the
energy expenditure of a human body through exercise or involuntary activity.
As a unit of measure, 1 small calorie is the amount of energy required to heat 1 millilitre
of water by 1 degree centigrade.
Whereas 1 large calorie is the amount of energy required to heat 1 litre of water (which is
1,000 millilitres) by 1 degree centigrade.
Food packing uses the large calorie unit of measure when stipulating it's calorie content.
So it's always best for consumers to use large calories to measure with.
So, what we're saying is, if you filled the kettle with 1 litre of water (which is 1,000
millilitres) to make a round of teas, it would require 100 calories to bring that water up
to boiling point, which is 100 degrees centigrade.
That's your temperature change (0-100 degrees), time the volume of water (1,000 millilitres)
which equals 100,000 small calories.
Then divide that by 1,000 to convert it to large calories, and that equals 100 large
calories to heat 1 litre of water to 100 degrees centigrade.
So, lets put that into perspective.
The amount of energy required to heat our water up to boiling point requires the same
amount of energy you'd fine in half a Mars bar, just under a full can of cola, 2 apples
or 50 stalks of celery.
Makes you realise doesn't it, how dense in energy some of these food and drinks can actually
be.
Now, on the flip side, to burn 100 calories worth of energy, that's equal to 10 minutes
worth of light cycling or 10 minutes worth of running.
For those still using the imperial system, or even worse, the imperial and the metric
system, a large calorie is the amount of energy required to heat 33.814 fluid ounces of water
by 33.8 degrees fahrenheit.
And it's also worth remember this is based on the temperature change happening in a controlled
environment and doesn't take into account factors such as energy waste, for example,
heat escaping from our kettle through the spout or sides during the heating process.
So it would likely require slightly more calories to heat water in a domestic environment.
However, the takeaway message is, by the most common standard, 1 calories is the amount
of energy required to heat 1 litre of water by 1 degree centigrade.
OK guys, thanks for watching.
If you want to learn more, check out my episode exploring why society today is so much more
overweight than in the 1950s.
Looking at changes in lifestyle and what we eat and how it has led to an obesity epidemic.
For more infomation >> My parrot is a smoker! - Duration: 0:42. 

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